Feature Request: Allow specifying the address when binding to a port

[lhchavez]

When opening a Java debugging session in my local machine, I'd prefer to be able to have the TCP port that the debug server will bind to in the loopback interface instead of in all of them, mostly out of paranoia when I'm working on a shared WiFi.

Also (and maybe less interesting to other folks), at replit.com, we detect TCP ports bound to 0.0.0.0 and treat them magically as web servers, so this should also prevent opening a debug session causing an unintended web server from being "deployed".

So I would like for it to be specify what interface and/or port the JavaDebugServer should bind to. Since the JavaDebugServer is a singleton, it might make sense to configure this through a system property (since sending this configuration in the initialize message may not have the intended effect if the LSP process had already spawned one JavaDebugServer instance). So something like

$ java \
        -Declipse.application=org.eclipse.jdt.ls.core.id1 \
        -Dosgi.bundles.defaultStartLevel=4 \
        -Declipse.product=org.eclipse.jdt.ls.core.product \
        -Dcom.microsoft.java.debug.serverAddress=localhost:12345 \  # <- a brand new property
        -noverify \
        -Xmx256m \
        -jar ../jdt/plugins/org.eclipse.equinox.launcher_1.6.100.v20201223-0822.jar \
        -configuration ../jdt/config_linux \
        -data /home/runner/JavaDAP \
        --add-modules=ALL-SYSTEM \
        --add-opens', 'java.base/java.util=ALL-UNNAMED \
        --add-opens', 'java.base/java.lang=ALL-UNNAMED

should do the trick.

[github-actions]

Hi lhchavez, I'm an AI Support assistant here to help with your issue. While the team reviews your request, I wanted to provide some possible tips and documentation that might help you in the meantime.

This is currently not supported by the Java Debug extension. There is no built-in setting to constrain the debug server’s listening address to localhost. You can work around this by launching your target JVM manually with JDWP agent arguments:

• Add a “launch” configuration in your .vscode/launch.json:

  {
    "type": "java",
    "name": "Launch with custom agent",
    "request": "launch",
    "mainClass": "com.example.Main",
    "vmArgs": "-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=localhost:12345"
  }

• Then use an “attach” configuration to connect:

  {
    "type": "java",
    "name": "Attach to custom agent",
    "request": "attach",
    "hostName": "localhost",
    "port": 12345
  }

Duplicate issues: none.

Other references with high confidence:

• Process Picker broken when JVM binds to random port
  Discusses the “address” attribute and workarounds for random ports
  Process Picker broken when JVM binds to random port vscode-java-debug#1121

Other references with low confidence

• Favorites support Debug mode
  Shows how to use “attach” configs in launch.json
  Favorites support Debug mode vscode-maven#444 (comment)

• Support for mvnDebug
  Feature request for Maven plugin to support mvnDebug
  Support for mvnDebug vscode-maven#49 (comment)

The team will respond to your issue shortly. I hope these suggestions are helpful in the meantime. If this comment helped you, please give it a 👍. If the suggestion was not helpful or incorrect, please give it a 👎. Your feedback helps us improve!